Page 363 - Construction Waterproofing Handbook

REMEDIAL WATERPROOFING 8.23
Epoxy injection is a restoration system as well as a waterproofing system. Injection can
restore substrates to a sound condition before waterproofing application, or be used as
waterproofing itself by stopping leakage through a crack.
Epoxy injection has been used on concrete, masonry, wood, metal, and natural stone
substrates. Large wood timber trusses in historic structures have been restored structurally
with epoxy injection systems. Typically, epoxy injection is used to restore concrete and
masonry substrates to sound condition.
Cracks to be injected must be large enough to allow entrance of epoxy, approximately
5 mil thick, and not so large that material flows out, 35–40 mil. Cracks that meet these size
limitations can be injected through any of the above listed substrate materials.
Application is completed by the pressure injection method using surface-mounted or
drilled ports through which to apply epoxy. In some cases, for example, horizontal surfaces
such as parking decks, epoxy is installed by the gravity method, in which epoxy simply
penetrates by gravity. In all cases a low-viscosity material is used, to allow for better epoxy
penetration into a substrate.
Surface-mounted ports are applied directly over a crack surface (Fig. 8.19). Drilled
ports require a hole to be drilled at the crack location and a mechanical packer placed into
these holes for injection (Fig. 8.20). Drilled ports are required for large, deep cracks, to
allow complete saturation of cracks with epoxy.
In both port applications, cracks are sealed with a brushed-on epoxy to prevent epoxy
from coming out of the crack face during injection. The port surround is also sealed and
adhered completely to substrates, preventing them from blowing off during injection.
If cracks penetrate completely through a substrate, the backside must also be sealed before
injection.

FIGURE 8.19 Surface-mounted ports for injecting epoxy
under low pressure. (Courtesy of Webac)